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AUTOMATIC SAFETY PILOT Christian S. Andersen, Warren, Pa., assignor to Pennsylvania Furnace & Iron 00., Warren, Pa., a corporation of Pennsylvania Application September 8, 1937, Serial No. 162,859

1 Claim.

This invention relates to an automatic safety pilot and more particularly to a fuel pilot associated with a burner and so arranged that upon the extinguishing of the pilot means is automatically actuated to shut off the fuel supply to the associated burner and to the pilot itself.

One of the features of my invention is the provision of a pilot having two thermostatic elements associated therewith, the arrangement being such that upon the extinguishing of the pilot the cooling of the thermostatic elements causes a shutting ofi' of the fuel supply to the burner associated with the pilot and also cuts off the fuel to the pilot itself.

Other novel features of my invention will be apparent from the accompanying drawing and description and the essential features will be set out in the claim.

In the drawing, Fig. 1 is a diagrammatic view partly in section showing pilot, a burner and a control valve for the burner in connection with my improved pilot device, and Fig. 2 shows a modified form of device where the burner control valve is electrically operated.

Referring to Fig. 1, I have illustrated one form of burner and control member with which my improved pilot means is adapted to operate. I have shown at m a fuel burner member such as is commonly found in water heaters, furnaces and the like, the same being supplied with gas through conduit ll, cock l2, valve l3 and conduit l4. The valve i3 has a port l3a which is opened and closed by diaphragm I5 above which is the chamber 06 formed between the diaphragm and the upper part of the valve casing. Through diaphragm i5 is a small vent i5a. This valve is of the type which is automatically closed by the diaphragm when the pressure on opposite faces thereof is equal but is opened when the pressure below the diaphragm preponderates over the pressure in chamber it.

At ii I have illustrated a pilot having suit-.

able openings l'la along the sides thereof from which gas jets emerge when the pilot is operating and it will be understood that in actual practice this pilot is alongside the burner In in position to light the burner when the gas is turned on. A manually controlled gas supply for the initial lighting of the pilot is by way of supply conduits i8 and i9 and valve 20. This conducts gas directly to the discharge chamber 2| in casing 22 and the gas passes through the chamber and the restricting opening 23 to the pilot IT. The valve 20 is a normally closed inlet valve which is operated in the well known manner by pressure on the button 20a. For establishing the permanent supply to pilot I! after its initial lighting, a thermostat 24 is provided. This thermostat has a casing 25 relatively expansible by heat and a central rod element 26 relatively non-expansible by heat. This is a well-known construction by. which heating of the thermostat will cause movement of the casing 25 outwardly, carrying the rod 26 with it so as to permit opening of the valve controlled thereby. The lower end of rod 26 enters discharge chamber 2|, where it is rounded to correspond to a seat 21a. of valve 21 which when the thermostat is cold engages valve seat 28 so as to keep the valve closed. A spring 29 lying within an inlet chamber below the valve urges the valve toward open position so that when the thermostat is heated spring 29 opens the valve and establishes the permanent supply of fuel to the pilotby way of conduits l8 and 30 and said inlet chamber. Valve 200 may then be released.

When the burner I0 is not in operation valve I3 is closed because gas at line pressure passes through the vent I5a. but is'unable to escape through conduit 3| as conduit 32 is closed by valve 33 and conduit 34 and the inlet chamber to which it leads are closed by valve 35. Pressure is thus equalized on opposite faces of diaphragm l5 and valve l3 will remain closed. Valve 35 is controlled by thermostat 36 which is similar to thermostat 24 and has an outer thermally expansive casing 31 and an inner non-expansive rod 38 abutting the seat 35a of valve 35. A spring 39 lying within the inlet chamber beneath valve 35 urges said valve toward open position. It results from this construction that when pilot I! is lit the gas jets impinging on thermostat 36 causes the opening of valve 35 whereupon conduit 34 is vented through the inlet and discharge chambers in casing 22 and through the restricted opening 4| in a bleeder 42. This reduces the pressure in chamber It so that the gas pressure below diaphragm l5 causes valve l3 to open, supplying gas to burner III which is lit by the pilot.

Valve 33 is diagrammatic only and may be taken to represent any one of a number of well known control devices often utilized for shutting off a valve similar to l3 by a room temperature thermostat, a high boiler pressure control, a low water boiler control and the like. Such devices when used in connection with a valve similar to 13 are arranged to open a valve in the position of 33, thus dumping gas into the chamber I6 and closing valve l3. This is a. control arrangement having nothing to do with the action of the novel pilot means.

When the pilot has been lit as previously described and has warmed up the thermostatic elements 24 and 36, the pilot will remain burning, supplied through open valve 21, valve l3 will remain open so. long as chamber I6 is vented through open valve 35, and the burner III will remain in operation. Upon the extinguishing of pilot I1, as for instance if the same should be bldwn out, thermostats 24 and 36 will be cooled, resulting in a contraction of casings 25 and 31, thus moving the rods 26 and 38 respectively downward, closing valves 2! and 35. The closing of valve 21 shuts off all gas supply to the pilot, the closing of valve 35 prevents the venting of the gas escaping throughthe vent 15a so that pressure in chamber [6 quickly builds up to the pressure below diaphragm l5 and valve [3 closes, thus shutting off all supply to burner I0. I have thus arranged a novel pilot means upon the extinguishing of which the fuel supply is shut off both to' the pil'otit'slf' and to its associated burner.

It will be observed that the pilot burner and valve controlling mechanism embodying the present invention is of extremely simple form, capable of manufacture, assembly and maintenance at low cost. The controlling parts are adapted for very convenient connection to and assembly with the supply line and diaphragm operated control valve for the main burner. The controlling parts are all formed as a part of, mounted within or attached to a single body member 22 which, for example, may be a single mass of cast metal such as brass, bronze or the like. This body member is bored out with two holes from each end, the upper holes forming the discharge chambers 2| and 40 and the lower holes the inlet chambers beneath supply to the main burner may be safely controlled in such manner that if the pilot flame goes out for any reason whatsoever the supplies of gas both to the pilot and main burner are fully turned.

off.

In the modification of Fig. 2, pilot I! and thermostat 24 are exactly as described in connection with Fig. 1 and the initial supply for the pilot is through conduit l9 and valve 20, as previously described, and the maintaining supply through conduit 3!] controlled by valve 21, as disclosed in Fig. 1.

However, in this modification I have shown the supply for burner III or the like through conduits I l and I4 controlled by valve 43, which is operated by any suitable electrical means, as, for instance, the solenoid 44. A thermostatic element 45 mounted adjacent the pilot l'l controls the operation of valve 43. The thermostat here shown is of the bimetallic type. The thermostatic element is secured at 46 to casing 22 and controls an electric circuit through supply lines 41 and 48 to solenoid 44. Line 41 includes switch 49 which is actuated by push rod 50 and adjustable contact 5| in response to movement of thermostat 45. In the modification of Fig. 2, after pilot II has been lit by manipulation of valve 20, thermostat 24 is heated as before, opening valve 21 and establishing the maintaining supply for the pilot through conduit 30. As pilot I! heats the bimetallic element 45 it moves so as to close switch 49, thus energizing solenoid 44, opening valve 43 to establish fuel supply for the burner ID, or the like. Upon the extinguishing of pilot I! thermostatic element 24 cools and closes valve 21, thus shutting off the gas supply to the pilot. Thermostatic element 45 cools and returns to the position of Fig. 2, opening switch 49, whereupon valve 43 is arranged to close by any suitable means such as gravity, a spring or the like. Thus this modification, as in the form shown in Fig. 1, shuts ofi gas supply to the burner associated with the pilot and to the pilot itself.

What I claim is:

Burner and valve control mechanism of the character described, comprising a main burner, a gas supply pipe therefor, a vented diaphragm op eratgd controlling valve for said burner, a single bodysmefiiber provided with two discharge chambers and two inlet chambers, two thermostats threaded into said body member, a'valve operated by each thermostat and controlling communication between an inletchamber and a discharge chambena pilotburner mounted between the two thermostats andoperating both thereof and communicating with one discharge chamber, the other discharge chamber being open to atmosphere, a pipe connecting the pilot burner inlet chamber to said main burner supply pipe, and a pipe connecting the other inlet chamber to the diaphragm pressure relief chamber of said control valve, whereby the pilot flame controls the gas supply to both the pilot burner and the main burner.

CHRISTIAN S. ANDERSEN. 

